GB821180A - Glass bending lehr - Google Patents

Abstract

821,180. Bending glass sheets. PITTSBURGH PLATE GLASS CO. April 3, 1957 [June 28, 1956], No. 10923/57. Class 56. [Also in Group XII] In a glass bending lehr in which sheets 4 are mounted on concave skeleton moulds 5 traversed by rollers 6, bending in the section B is controlled by directing cooling air against the sheets through controllable pipes 7a-7e arranged as a longitudinal series of transverse rows. Air from a reservoir 12 passes by a main reducing valve 13 to a main 11 provided with branch pipes 9 feeding each row of pipes 7a- 7e, the latter being provided with individual valves 8. A solenoid-operated valve 10 in a branch pipe 9 over-rides the control of the individual valves 8. The latter are preset manually and the valves 10 may be opened only when the mould is immediately above them, as by an arm 28 on the mould contacting a field arm 29 adapted to operate an electric control circuit. Figs. 3-5 (not shown), illustrate the controls required to cool portions of car windscreens with a flat central portion and slightly bent wing portions, a sharply bent control portion, and a sagging central portions respectively. The lehr has upper banks of heaters 2, and banks of recessed wall heaters 3, the latter being most numerous in the preheating section A. Specifications 804,576, 804,577, 804,578 and 804,579 are referred to.